Fire-extinguishing method and apparatus



169-47. :oR 2041.456 R SQEECQ RQGFTE Feb. 8, 1944. c. A. GETZ 2,341,436

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FIRE EXTINGUISHI NG METHOD AND APPARATUS Filed Jan. 21, 1.942

7IIIIIII 4 sheets sheet 4 Seanzh Roam Patented Feb. 8, 1944 UNITED STATES PATENT OFFICE FIRE -EXTINGUISHING METHOD AND APPARATUS Charles A. Getz, Glen Ellyn, Ill., assignor, by mesne assignments, to Reconstruction Finance Corporation, Chicago, IlL, a corporation of the United States Application January 21, 1942, Serial No. 427,650

22 Claims.

This invention relates to methods of employing carbon dioxide for extinguishing fires involving large quantities of highly inflammable liquids confined in quench or storage tanks, pools, dikedin areas, o the like, and discharge apparatus suitable for carrying out the methods.

The extinguishment of fires involving large quantities of highly inflammable liquids which are confined so that the combustion zones are mixture through smothering or diluting and/or by preventing the temperature of the fuel mixture from eaching its ignition value through cooling of either the liquid vapors or the oxygen or both.

It has been determined by extensive experiments that the space left between the liquid surface and the bottom limit of the combustion zone, or the extreme lower portion of said zone, prolocated above the top surfaces of the liquid bodies vides the most favorable location for carrying presents a difficult problem. The liquids as such on this smothering, diluting and/or cooling opwill not actually ignite or burn, however, the eration when carbon dioxide is employed as the vapors from such liquid, supplied with the proper extinguishing medium. When the body of liquid amount of oxygen from the atmosphere, will is confined within the side walls of a tank, a pool, form a fuel mixture which, when heated to the or a dike, with the top surface of the liquid 10- proper temperature, will ignite and burn very cated below the top edges of said walls, the above readily and will create an extremely intense fire. referred to space, or the lower portion of the As the combustible fuel mixture is not formed combustion zone, must be defined by at least a right at the surface of the body of liquid and does portion of the height or depth of said walls. not exist until the rising vapors have had an Therefore, if the extinguishing action is carried opportunity to mix with the proper amount of on substantially at the top edges of said side oxygen, and as the combustible fuel mixture will walls, or at a level below said edges, the side not ignite until its temperature has been raised walls will form a barrier which can be relied to the kindling value, the bottom limit of what upon for help in either completely preventing oonsitutes the actual combustion zone is always the upward flow of vapors or in effecting dilution located a substantial distance above the surface of the vapors. This barrier also makes possible of the liquid. The space left between the surface the use of a materially reduced amount of carbon of the liquid and the bottom limit of the comdioxide to effect the desired cooling operation. bustion zone, therefore, is filled with liquid va- To be more explicit, the carbon dioxide may pors and oxygen. Substantially pure liquid vabe discharged in a proper condition and manner pors are released from the surface of the body to effect th formation of a dense, continuous, of liquid. Progressively increasing proportions horizontally arranged curtain, of a relatively of oxygen become mixed with the vapors as they small thickness, which extends across the entire rise toward the combustion zone. Of course, the area defined by said walls. This curtain may bottom limit of the combustion zone is estabbe located in the aforesaid fuel forming space or lished at the level at which the proper amount it may be located so that it will cut through the of oxygen has been mixed with the vapors to lower portion of the combustion zone. Regardform the combustible fuel mixture. The temperless of the exact location, the flow of vapors to ature of the pure liquid vapors that are liberated th combusion Zone above the curtain will be from the surface of the liquid body, of course, completely shut off or such vapors as do pass is the same as that of the liquid. This temperaupwardly through the curtain will be diluted to ture increases progressively and very rapidly as such an extent that a combustible fuel mixture the vapors and the entrained oxygen rise until cannot be formed even when an abundant supthe ignition temperature is finally reached when ply of oxygen is available. If some of the fuel the fuel mixture arrives at the bottom limit of forming vapors should happen to flow through the combustion zone. the aforesaid curtain, as it is being formed dur- The expression extinguishing a fire merely ing th initial discharge of the carbon dioxide, means to render non-combustible the fuel subwithout becoming sufiiciently diluted, their passtance that is feeding the fire by either changsage in heat exchange relation with the cold ing its physical characteristics so that it will not carbon dioxide will lower their temperature to burn, or by preventing the fuel substance from such an extent that they will not ignite readily being heated to its kindling or ignition point. when they reach the lower limit of the com- This desired result can best be accomplished with bustion zone. a fire involving highly inflammable liquids by The locating of the extinguishing curtain at a preventing the formation of a combustible fuel level which substantially corresponds with the plane occupied by the top edges of the aforesaid confining side walls will effect cooling of a substantial portion of the oxygen flowing to any liquid vapors which have passed through the curtain. This cooling action results from the movement of the oxygen horizontally inwardly in heat exchange relation to the top of the curtain. The inward flow of oxygen toward the area that overlies the center of the body of liquid is caused by the low pressure area or suction produced by the strong updraft which is centered over that area.

It will be appreciated, of course, that th curtain will prevent any oxygen from reaching the vapors that are trapped in the completely closed chamber that is defined by the top surface of the liquid, the side Walls of the tank, etc., and the curtain which parallels the suface of the liquid and extends across the entire area defined by said side walls. Even if th curtain is created at a level which causes it to pass through the lower portion of the combustion zone, thereby severing this lower portion from the remainder which is located above the curtain, the failure to obtain a sufficient amount of oxygen to support combustion will cause this severed lower portion to cease to exist.

In cases where the hazards to be protected consist of storage or supply tanks, in connection with which the liquids are being withdrawn and replenished, the liquid level, naturally, will not remain fixed with respect to the top edges of the confining side walls. The location of the combustion zone will, of course, vary with respect to the top edges of the side walls to the same extent as the variations in liquid level. If the variations in the location of the combustion zone are too pronounced, or cover too large a range, for an extinguishing curtain that is maintained at a fixed level at or relatively close to the top edges of the confining walls, it then becomes necessary to mount the discharge apparatus for the carbon dioxide on some form of support which may be either automatically or manually raised or lowered to follow the varying liquid level. Mechanisms which will accomplish this desired result are very old in the art and for that reason they need not be disclosed. Merely by way of example, it i noted that a support in the nature of a float will accomplish automatic adjustment of the discharge apparatus,v A flexible section in the supply pipe or pipes for the extinguishing medium will take care of adjustments of the discharge apparatus.

It will be appreciated that in effecting discharge of carbon dioxide to form a curtain which will be arranged in relatively close, parallel relation to the top surface of the body of inflammable liquid being protected, the discharge must be of such a character that it will not blow or splash the liquid outside of its confining tank, etc. If such blowing or splashing were to occur, the fire would be spread beyond the operative limits or range of the extinguishing apparatus.

Although the above described method of discharging carbon dioxide in such a manner as to form a curtain was developed for the primary purpose of extinguishing fires involving confined bodies of inflammable fluids, any person experienced in the art to which this invention relates will appreciate that the curtain formed by the discharge can be used for other purposes, such as covering a surface over which inflammable liquid may be flowing.

It is the primary object of this invention to provide a method of employing carbon dioxide for extinguishing fires involving large bodies of highly inflammable fluids which are confined in tanks, pools, diked-in areas, or the like.

A further important object of the invention is to provide a method of the aforementioned type in connection with which carbon dioxide is discharged in such a condition and manner that a dense, continuous curtain is formed which extends across the entire area between the side walls of the confining tank, pool, or dike with the result that the space within the tank, etc., and below the curtain is completely shut off from the space above the curtain.

Another object of the invention is the provision of a method of extinguishing inflammable fluid fires by creating a carbon dioxide snow and vapor curtain in relatively close, parallel relation to the surface of the liquid being consumed so that blowing or splashing of any of the liquid from its confining tank, pool, diked-in area, or the like will not occur.

Still another primary object of the invention is the provision of a method of discharging carbon dioxide in such a manner as to form a dense, continuous curtain that is made up of snow and vapors, the said curtain being formed so as to extend entirely across a certain area which may be either above and parallel with the surface of a confined body of inflammable liquid or parallel with a surface over which such a liquid is flowmg.

A further primary object of the invention is the provision of carbon dioxide discharge apparatus which is capable of forming the aforesaid curtain for carrying out the methods referred to above.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a top plan View of a quench or dip tank assembly with the apparatus of this invention properly associated therewith,

Figure 2 is an end elevational View of the assembly of Fig. 1,

Figure 3 is an enlarged View, partly broken away, showing the discharge apparatus of this invention properly applied to the tank assembly of Figs. 1 and 2,

Figure 4 is a fragmentary, enlarged, vertical sectional view of the upper portion of one side wall of the assembly with a portion of the carbon dioxide discharge apparatus properly associated therewith,

Figure 5 is a fragmentary, side elevational view of the upper portion of a tank side wall showing the slot which is formed in said wall to allow for the discharge of the carbon dioxide snow and vapors to form a part of or all of an extinguishing curtain,

Figure 6 is a detail perspective View of an end plate which is employed for supporting the carbon dioxide discharge pipe which forms a part of the discharge apparatus,

Figure 7 is a detail perspective view of an intermediate supporting bracket for the discharge pipe.

Figure 8 is a detail perspective view of a type of supporting plate or reinforcement which is employed for strengthening the tank wall where it is slotted in the manner illustrated in Fig. 5

a, r rmsarss, a l (WE EXUN 1 s wmil ileum Figure 9 is a top plan view of a storage or supply tank for highly inflammable fluids which is surrounded by a diked-in area to prevent spreading of any of the fluid which may leak from the tank and with the discharge apparatus of this invention properly applied to provide full fire extinguishing protection for the tank and the said area.

Figure 10 is a partly side elevational view and partly vertical sectional view of the tank and dike of Fig. 9, and

Figure 11 is a detail, enlarged vertical sectional view which discloses the carbon dioxide discharge apparatus properly associated with the interior and exterior of the upper portion of the storage tank side wall.

In the drawings, wherein for the purpose of illustration are shown the preferred embodiments of this invention, and first particularly referring to Figs. 1 and 2, the reference character l2 designates in its entirety a quench or dip tank assembly which is of more or less conventional design. This tank is ordinarily employed for subjecting different sized objects or articles to different types of quenchin and/or clipping treatments in dilferent bodies of fluid which are usually of an highly inflammable character. For example, in heat treating certain metallic objects, it is necessary to subject the same to a cooling or quenching bath which usually consists of a suitable type of oil. This oil is highly inflammable and it occasionally is ignited as a result of carelessness or an accident on the part of the men making use of the same. When a fire occurs, it is highly desirable to be able to quickly extinguish the same so that th fluid of the bath will not be heated to a temperature which would be unsuitable for use and, of course, the fire should be quickly extinguished without contaminating the liquid with the extinguishing medium. A more obvious reason for quickly extinguishing the fire is to prevent it from spreading to other portions of the plant or shop in which the tank assembly is used.

This quench or dip tank assembly is being employed solely for the purpose of illustrating one application or use of the method and apparatus embodying this invention. It is to be understood, therefore, that the selection of a quench or dip tank assembly per se or an assembly of a particular type is not to be considered as limiting the invention. As the detail features of construction of the tank assembly are not important insofar as this invention is concerned, they will not be illustrated and described to any considerable extent.

The plan view of Fig. l'illustrates the tank assembly as including opposite side walls l3 and I4, opposite end walls l5 and IS, a transverse partition I! which extends between the side walls I3 and M, and a longitudinally extending partition l8 which extends between the end wall l6 and the transverse partition I1. It will be seen that the transverse partition divides the interior of the tank assembly into two halves while the longitudinal partition [8 divides one half of the tank assembly into two parts. We have, therefore, a single tank chamber which is defined by the end wall l5, portions of the side walls l3 and I4, and the partition Il. This large tank chamber may have its bottom wall 19 positioned near the supporting floor so as to provide depth which will cooperate with the horizonta dimensions to accommodate sizable objects. The remainder of the assembly is divided into two quenching or dipping compartments which are defined by the end wall I6, portions of the front and rear walls l3 and M, the longitudinal partition l8, and the transverse partition IT. The bottom walls for these two smaller com- .partments may be arranged at the same level as the bottom wall l9 for the larger compartment or smaller tank compartments of less depth, and different depths, may be provided by arranging the bottom walls for these two small compartments at different elevations.

To permit the two smaller compartments to be covered up or closed off when not in use, covers or lids 20 may be provided for the same. Two similar lids 2| are provided for the large compartment of the assembly. Either or both of these last-mentioned lids or covers may be closed or opened in accordance with the desires of the users of the assembly.

These various covers or lids 20 and 2| are hinged at their inner longitudinal edges to a plate 22 which extends longitudinally of the tank assembly and rest on the end walls l5 and I6 and the partitions I! and [8. Each lid is provided with a counterbalancing mechanism which includes a cable or cord 23 that is attached at its outer end to the outer portion of the lid or cover and is trained over a sheave 24 mounted in the upper portion of a vertically extending box or well 25 that houses for vertical sliding movement a weight 26 attached to the inner end of the cable or cord.

It has been explained above that the fire extinguishing methods and apparatus embodying this invention operate on the principle of creating an extinguishing curtain which covers the entire horizontal area or cross section of a tank interior; i. e., the entire area defined by the confining walls which in reality may be side or end walls or partitions. In referring to these confining walls in the language of the claims, the term side walls will be employed to generically refer to what actually may be side walls, end walls or partitions and the claims should be construed with this generic use in mind. Because of the horizontal dimensions of the large compartment formed by the side walls I3 and I4, the end wall l5 and the partition ll, it is necessary to discharge the carbon dioxide employed for forming the extinguishing curtain from opposite confining walls. The discharging apparatus in Figs. 1 and 2 is generally designated by the reference character 2! and is shown as being associated with the side wall portions l3 and I4. These discharge devices, however, could just as well be associated with the end wall l5 and the partition H. In fact, if the horizontal dimensions of a tank are large enough, it will be necessary to associate the discharge apparatus with all of the side margins of the compartment. These discharge devices 21 receive liquid carbon dioxide from the common supply pipe 28 with its branches 29, A suitable control valve may be provided at any desired point in the common line 28. This control valve may be either manually or automatically actuated to effect delivery of the liquid carbon dioxide to the discharge devices 21.

One discharge device 21 is provided for each of the smaller compartments because the horizontal dimensions of the latter are such that a continuous curtain may be formed over the entire area of a compartment by discharging from only one confining or marginal wall. These discharge devices 21 may be independently supplied with liquid carbon dioxide by the separate pipes 30. Suitable automatically or manually controlled valves may be arranged in these pipes 30 to efiect proper delivery of the liquid carbon dioxide to the separate discharge devices 21.

Figs. 2, 3 and 4 disclose the carbon dioxide discharge devices as being located exteriorly of the tank walls. It is necessary, therefore, to provide openings in the walls to permit passage of the carbon dioxide snow and'vapors which are employed for creating the extinguishing curtain. Fig. 5 illustrates the upper portion of the side wall l3 which is associated with and constitutes one defining wall of the large compartment. This upper wall portion has an elongated slot 3| cut therein. This slot permits the carbon dioxide from one of the discharge devices to be delivered into the tank compartment. It is to be understood that a similar slot is provided for each one of the remaining three illustrated discharge devices 21.

Figs. 3 and 4 disclose a channel-shaped plate as being attached to the outer face of the side Wall in a manner to cooperate with this side wall for forming an expansion chamber 32 for the carbon dioxide with the slot 3| functioning as the outlet or discharge opening for this chamber. The channel-shaped plate may be more specifically described in connection with the disclosure of Fig. 4. It includes a top wall 33 which is welded at 34 to the top edge flange 35 of the side wall l3. This top wall 33 is carried by an outer side wall 36 that is joined at its longitudinal, lower edge to a bottom Wall 31. A base flange 38 is joined to the free longitudinal edge of the bottom wall and is welded at 39 and 4|. to the portion of the side wall I3 located below the slot 3|.

The opposite ends of the carbon dioxide expansion chamber 32 must necessarily be closed. Figs. 3 and 6 illustrate end plates 42 and 43 for performing this function. Plate 42 is provided with an opening 44 which allows for the passage of the discharge pipe 29 into the chamber. The end plate 43 is not provided with an opening 44 because the pipe 29 does not have to pass therethrough. These plates 42 and 43 are Welded at 45 to the opposite end portions of the chamber forming channel plate.

Because of the need for forming the slot 3| of a length which, for all practical purposes, is substantially equal to the horizontal dimension of the tank wall portion that defines one side of the inflammable fluid confining compartment, this wall of the tank is materially weakened and it must be properly reinforced. Figs. 3, 4 and 8 disclose reinforcing bars or plates which are used for this purpose. These plates 46 are spaced at suitable intervals along the chamber 32 and slot 3|. They are of proper length to have their ends 41 welded to the inner face of the outer side wall 36 of the channel and to have their remaining ends 48 fitted in the slot 3| and welded to the top and bottom edges of said slot. The bottom edge 49 of each one of these plates may be welded to the inner surface of the bottom wall 31 of the chamber forming channel. It will be appreciated that these reinforcing plates 46 will overcome any weakness of the side wall of the tank that is produced by the formation of the slot 3|. These plates also help to prevent warping or buckling of the chamber forming channel plate as a result of becoming heated by a fire that is consuming the fluid 50 confined within the chamber of the tank.

For the purpose of properly supporting the portion of the carbon dioxide discharge pipe 29 which extends the length of the expansion chamber 32, brackets 5| are provided at suitably spaced intervals. These brackets are shaped at their top to provide a pipe supporting cradle or notch 52. The outer and bottom edges 53 and 54 respectively are shaped and arranged to permit them to be welded to the inner face of the outer side wall 36 and the inner face of the bottom wall 31 of the expansion chamber 32. The remaining edge portion of each bracket is provided with a rectangular projection 55 that is of proper size to enter the associated slot 3|. This projection may be welded to the top and bottom edges of the slot so that it will perform the function of an additional reinforcing bar for the slot; 1. e., each bracket will take the place of a reinforcing bar 46.

The carbon dioxide discharge pipe 29 is illustrated in Figs. 3 and 4 as extending lengthwise of the expansion chamber 32. The inner end of this pipe is closed by any suitable means, such as the Welded plug 56. Liquid carbon dioxide discharge orifices 51 are provided at suitable intervals along the length of the portion of the pipe 29 which is arranged within the expansion chamber.

By inspecting the vertical sectional View of Fig, 4, it will be noticed that the carbon dioxide discharge pipe 29 is positioned in the upper portion of the chamber and approximately as close to the inner surface of the top wall 33 of the chamber and the outer surface of the associated side wall of the tank as is permissible and yet leave material at the top and inner sides of the hole 44 in the end plate 42 of the chamber. These spacings of the periphery of the pipe relative to the inner surfaces of the top and inner wall portions of the chamber may be in the neighborhood of from to of on inch. The outside diameter of the pipe should bear a proper relationship to the width of the upper portion of the chamber 32 so as to leave a gap of from approximately onequarter of an inch to one-half of an inch between the outer side of the pipe and the inner, opposed surface of the chamber wall 36.

Of course, the size of the pipe, the size of the discharge orifices 51, the spacing of these orifices, and the height of the final discharge slot or opening 3| must all bear an approximate relationship to each other and to the vapor pressure of the liquid carbon dioxide delivered to the discharge portion of the pipe so that a proper velocity of discharge will result. The angle of the discharge orifices 5'! with respect to the plane of the final curtain discharge also must bear an approximate relationship to bring about the desired travel of the carbon dioxide snow and vapors to effect segregation of the same into layers or laminae.

The following figures will be presented as ex emplary for these various factors. A threequarter inch standard pipe of proper strength has been found to be a very practical size for all but the very largest installations. If necessary, pipe sizes up to an inch and a half can be em ployed. The remaining figures will apply to the three-quarter inch pipe. An orifice diameter of a hundred and twenty thousands (.120) of an inch is very satisfactory. These orifices should be spaced approximately six inches from each other. The orifices may be arranged relative to the horizontal anywhere between approximately a 45 angle above the horizontal to approximately a 10 angle below the horizontal. The vertical dimension or heighth of the discharge slot 3| may be approximately one inch.

ltt. HRE EXTlNmnsarrs.

The above figures are ideal when liquid carbon dioxide stored at a vapor pressure of approximately three hundred pounds per square inch is employed as the source. It will be pointed out again, however, that the above noted figures are given primarily for the purpose of providing a complete disclosure of the best mode in which the principles of the invention may be applied. Therefore, they should not be considered as restricting or limiting the invention to the recited values.

What actually happens to the carbon dioxide from the time it is released from the discharge pipe 29 up to the time it is delivered into the liquid confining tank may best be described in connection with the disclosures of Figs. 3 and 4. The liquid carbon dioxide in the bore of the pipe 29 is under its own vapor pressure. This pressure must be above '75 pounds per square inch, absolute, to maintain the carbon dioxide in its liquid form and to prevent plugging of the discharge orifices 51 with solid carbon dioxide. When this liquid carbon dioxide is discharged or released through the orifices, it expands very suddenly and is converted to a mixture of vapors and snow particles. The aforementioned permissible angle of discharge of the orifices relative to the plane of the final discharge, and, therefore, the location of the slot 3|, will cause the vapor and snow mixture to travel through the chamber in a generally transverse direction to reach the slot 3|. While confined in the expansion chamber 32 during this transverse travel, the carbon dioxide released from the several orifices will naturally expand laterally or spread out and will merge before reaching the slot 3| to form a continuous mass that will be equal in length to that of the chamber. That is to say, the lower portion of the chamber will be filled with the mixture of snow and vapors.

The total area of the discharge slot 3| may bear any desired relationship to the total area of all of the discharge orifices 51 so as to provide the proper Velocity of discharge through the slot 3|. It will be appreciated that the discharge from the slot 3| must have a sulficiently high velocity to provide the required reach or range so as to form a curtain of the desired dimensions. Due to the shape of the slot 3|, the discharged snow and vapors will take the form of a curtain which will extend or stretch horizontally across the tank compartment in relatively close, parallel relation to the top surface of the liquid body. When only one discharge device is employed, the velocity of the discharge should be sufiicient to cause the curtain formation to be maintained throughout the entire width of the horizontal area of the liquid compartment. If two opposed discharge devices are employed in a single compartment, the velocity of each discharge should be sufficient to cause its curtain forming portion to extend at least slightly more than half way across the area of the compartment if it were not interfered with.

This curtain, which is made up of dense snow particles and vapors will function to either completely prevent the flow or movement of the vapors rising from the surface of the liquid upwardly to the combustion zone above the curtain or it will dilute the vapors to such an extent that they will not form a combustible fuel mixture when it is possible for them to become mixed with oxygen from the air above the curtain. The curtain, also, will prevent any oxygen Search Room from reaching the vapors that are positioned between the curtain and the surface of the liquid.

As the hottest portion of the fire and the strongest up-draft will be found over the center of the top surface of the liquid body, unless the tank of liquid is located where it will be subjected to natural winds, drafts, or the like, the use of opposed discharge devices is found to be especially desirable. This is due to the fact that the carbon dioxide snow and vapor discharges which form the opposite halves of the extinguishing curtain will meet at the transverse center of the area being treated. When these two curtain forming discharges meet, the mixtures of snow and vapors will be compelled to depart from their horizontal direction of travel and will move upwardly and downwardly. The carbon dioxide which is compelled to move upwardly will travel into the combustion zone Where it will have a very desirable cooling effect on the products of combustion and the fuel being consumed. The carbon dioxide that is compelled to move down wardly will be retained in the space between the top surface of the liquid body 50 and the bottom of the dense curtain formation. This downwardly deflected material will thoroughly dilute the liquid vapors rising from the surface of the body 50. Snow particles will be deposited on the surface of the liquid. It will be found upon inspecting a tank, after a fire has been extinguished by this curtain form of discharge, that floating islands of snow will be seen on the surface of the liquid.

Referring now to the disclosure of Figs. 9 to 11 inclusive, it will be seen that this method of extinguishment has been applied to an inflammable liquid storage tank 60 and the diked-in area 6| that is usually provided around tanks employed for storing oils, gasoline, and the like. The discharge apparatus 62 for the liquid in the tank 60 is located within the upper portion of the same. The discharge apparatus 63 for the diked-in area 6| is mounted on the top of the dike or embankment which defines this area. Due to the size and the circular formation of the tank 60 and the area 6!, the discharge devices 62 and 63 extend entirely around these hazards. These discharge devices, although they differ in shape from the discharge devices 21, referred to above, will function in exactly the same manner as the previously described devices and will create the extinguishing curtain in exactly the same manner.

Fig. 11 will be specifically referred to in connection with these devices 62 and 63 to explain their slightly different form of carbon dioxide expansion chamber. This difference in construction is made necessary by the fact that a slotted tank wall is not employed as a part of the chamher.

The chamber is fabricated from three different angle pieces 64, 65 and 66. The piece 64 forms the inner side wall of the chamber and part of the top wall and is welded to the tank at 64a. The piece 65 has a portion which completes the top wall of the chamber, another portion which forms the outer side wall, and a final portion which is welded at 61 to the inner surface of the side wall of the tank 60. The third angle piece 66 forms the bottom wall of the chamber and has a mounting flange portion which overlies the mounting flange portion of the angle piece 65. The discharge slot or opening 68 is formed between the bottom edge of the vertical branch of the angle piece 64 and the inner edge of the horizontal branch of the bottom angle piece 66. One bracing plate or bar 69 is illustrated in this figure. It will be understood, however, that a suitable number of bracing bars and pipe supporting brackets will be provided.

The carbon dioxide discharge pipe 10 is of circular formation in plan and is supplied by the pipe line I l The construction of the discharge device 63 for the dike of the area 61 is of substantially identical construction to the discharge device 62 and for that reason it need not be disclosed and described in detail. It will be sufiicient to say that an expansion chamber is formed by properly shaped and fabricated angle pieces. A carbon dioxide discharge pipe of circular formation is located within the chamber and is identified by the reference character I3. This discharge pipe is supplied with carbon dioxide by the line 14.

It will be appreciated that the discharge devices 62 and 63 will produce fire extinguishing curtains which will completely shut off the top area of the tank 60 and the entire area defined by the dike 6i and the periphery of the tank 60.

These two discharge devices, therefore, will extinguish any fires which have their combustion zones located above the curtained areas. The discharge device 63 for the diked-in area 6! will not be needed unless oil overflows the top of the tank 60 or is released through a crack or opening formed in the side wall of the tank. That is to say, the inflammable fluid will normally remain within the tank 60 unless an explosion occurs which provides some top or side wall opening in the tank. tank, the only combustion zone that will be formed will be located above the top of the tank. The discharge device 63 will not be needed to extinguish a fire confined to the tank. For more complete fire protection for the larger sized tanks, it will probably be desirable to arrange several discharge devices around the outside of and spaced along the heighth of the tank so that carbon dioxide can be discharged downwardly against the peripheral surface of the tank to extinguish any fire that is consuming liquid running down the outside of the tank. This latter form of discharge nozzle is illustrated in detail in Fig. 11. For all practical purposes, it is the same as the devices 21 and 62 of Figures 4 and 11 but because of the manner in which it is mounted on the exterior of the tank 60, a slightly different construction must be employed.

To allow the inflammable fluid that leaves the tank through an opening located at a point above a discharge device 15 to run down the outside surface of the tank wall past the said device and into the extinguishing range of the discharge from said device, a suitable number of supporting brackets 16 are provided. These brackets are spaced at proper intervals and are welded at 11 to the tank and at 18 to the channel shaped piece 79 which partially forms the expansion chamber 80. The remainder of this chamber is formed by the angle piece 81 which overlaps one flange of and is welded at 82 to the channel piece 19. A downwardly facing slot 83 is formed for the chamber 80 by the free edge portions of the pieces 19 and El. A suitable number of chamber bracing and pipe anchoring bars 84 are provided for the discharge device. The required carbon dioxide discharge pipe 85 is provided and is positioned in the chamber 80 in the manner illustrated in this figure. Supply pipe 86 will deliver If the liquid remains in the the required carbon dioxide to the discharge pipe 85.

By inspecting Fig. 10, it will be appreciated that each discharge device 15 will produce a curtain that will enclose a portion of the wall of the tank 60. The arrangement of these devices in a proper spaced relation with respect to each other will cause the curtain of the upper device to overlap the curtain of the lower device so that the entire height of the tank will be protected. Of course, the number of devices 15 to be employed will depend on the size of the tank and the reach or range of each device.

From the above description of the mode of operation of the carbon dioxide discharge apparatus embodying this invention, it will be appreciated that the snow portion of the discharge plays a very important part in the formation of the extinguishing curtain. In patent numbered 2,143,311, issued to Eric Geertz on January 10, 1939, there is disclosed and claimed a method of extinguishing fires which employs as the extinguishing method liquid carbon dioxide which is maintained in readiness for use at a substantially constant sub-atmospheric temperature and its corresponding vapor pressure. One of the outstanding novel features of this patented method, when compared with prior methods employing carbon dioxide stored at atmospheric tempera ture, is the improved extinguishing effect that results from the high percentage of snow yield obtained when the low temperature liquid carbon dioxide is permitted to suddenly expand. The lower the temperature at which the liquid carbon dioxide is discharged, the greater the percentage of yield of snow.

It will be appreciated from the above reference to the Eric Geertz patent that more favorable and efficient extinguishment will be accomplished with the method and apparatus of this invention if the liquid carbon dioxide is obtained from a low temperature source of supply because the higher percentage of yield of snow obtained from this low temperature liquid will permit a much more dense extinguishing curtain to be formed. The method and apparatus of this invention, however, can effectively employ liquid carbon dioxide that is obtained from a source which is at atmospheric temperature.

I am aware of the factthat prior to the development of the method and apparatus embodying this invention, carbon dioxide has been employed for extinguishing fires involving highly inflammable liquids confined in tanks, or the like, so that the combustion zones were located above the tops of the tanks. In the case of each such prior use, however, the carbon dioxide has been discharged from one or more nozzle structures which were so designed and arranged that a large, billowy cloud was formed. Before this cloud could effect extinguishment it had to be built up to a sufiicient size and it had to be properly arranged to completely encompass or embrace the top portion of the tank. A cloud of proper horizontal dimensions to accomplish that essential result was necessarily of such large dimensions in other directions that it would occupy a considerable portion of the surrounding atmosphere. Therefore, an unnecessarily large amount of carbon dioxide had to be discharged to create such a smothering cloud.

The extinguishing cloud formation of the prior art is vastly difierent from the very dense, compact, well defined curtain of this invention which is formed only within the margins of a tank and therefore requires a minimum amount of carbon dioxide to create. The curtain, although only a few inches in thickness at any point, is very dense because it is formed by the compact mixture of carbon dioxide snow and vapors. The cloud of the prior art, on the other hand, is only formed as a result of the carbon dioxide snow and vapors partaking of three dimensional motion, due to expansion, etc. The cloud, therefore, is very much less dense and requires a considerably greater thickness, or depth of the same, to effect the required smothering, diluting and/or cooling action.

It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the method steps and the shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. A method of employing liquid carbon dioxide for effecting extinguishment of a fire involving a body of highly inflammable liquid confined in a tank, or the like, comprising conducting liquid carbon dioxide through a path of confinement that extends along a wall structure of said tank discharging said liquid through a plurality ofconstricted orifices spaced at suitable intervals along and all facing radially in the same direction with respect to said path to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining in confinement in a single chamber the snow and vapors until all the separate discharges of the same merge along the entire length of said path, and finally effecting discharge of said merged snow and vapors along the entire length of said path at a sufficiently high velocity and in such a manner as to project a dense, relatively thin curtain which extends continuously across an area which is defined at least in part by said side wall structure of the tank.

2. A method of employing liquid carbon dioxide for effecting extinguishment of a fire involving a body of highly inflammable liquid confined in a tank, or the like, comprising conducting liquid carbon dioxide through a path of confinement that extends horizontally the entire length of a side wall of said tank, discharging said liquid through constricted orifices spaced at suitable intervals along said path to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining in confinement the snow and vapors until the separate discharges of the same merge along the length of said path, and finally effecting horizontal discharge of said merged snow and vapors along the entire length of said path at a sufficiently high velocity and in such a manner as to produce a dense curtain which extends continuously across the entire-area defined by all of the side walls of the tank and in spaced parallelism with the surface of the liquid body.

3. A method of employing liquid carbon dioxide for efiecting extinguishment of a fire involving a body of highly inflammable liquid confined in a tank, or the like, comprising conducting liquid carbon dioxide through a path of confinement that extends horizontally along the entire length of ,two opposed side walls of said tank, discharging said liquid through constricted orifices spaced at suitable intervals along said path to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining in confinement the snow and vapors until the separate discharges of the same merge along the length of said two side walls, and finally effecting simultaneous horizontal discharge of said merged snow and vapors along the entire length of said two walls at a sufiiciently high velocity and in such a manner as to produce a dense curtain which extends continuously across the entire area defined by all of the side walls of the tank and in swed parallelism with the surface of the liquid.

4. A method of employing liquid carbon dioxide for efiecting extinguishment of a fire involving a body of highly inflammable liquid confined in a tank, or the like, comprising conducting liquid carbon dioxide through a path of confinement that extends horizontally entirely around the side ,wall str u cture of said tank, discharging saidiiquidthirough constricted orifices spaced at suitable intervals along said path to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining in confinement the snow and vapors until the separate discharges of the same merge along the length of said' path, and finally effecting discharge of said merged snow and vapors along the entire length of said path at a sufiiciently high velocity and in such a manner as to produce a dense urtain which extends continuously across an area hiclr is defined at least in part by the side wall structure.

5. A method of employing liquid carbon dioxide for producing a cgrtamop snow and vapors entirely across all of an area to prevent the passage of undiluted vapors therethrough, comprising discharging liquid carbon' dioxide through constricted orificesipacefat suitabl intervals along certain portions of'said area to permit sudden expansioniiftlid'same to effect its conversion into snow and Vapors, -maintaining in confinement the snow and vapors formed by said separate discharges untilthe same merge into elongated masses equal in length to that of said area, and finally effecting discharge of snow and vapors from the lengths of said masses to produce the aforesaid curtain.

6. A method of employing liquid carbon dioxide for producing a curtain of snow and vapors entirely across a well e'iifi'ed open area to prevent the passage of undiluted vapors, comprising discharging liquid carbon dioxide through constricted orifices spaced at suitable intervals along a marginal portion of said open area to permit sudden expansion of the same to effect its conversion into snow and vapors, maintaining in confinement the snow and vapors formed by said separate discharges until the same merge into an elongated mass equal in length to that of said marginal portion, and finally effecting discharge of snow and vapors from the length of said mass to produce the aforesaid curtain.

'7. A method of employing liquid carbon dioxide for producing a curt aim of snow and vapors entirely across all of a well defined open area to length of said mass to produce the aforesaid curtain.

8. A method of employing liquid carbon dioxide for producing a curt a in of snow and vapors entirely across an area defined by a perpendicular side wall structure to prevent vertical move ment in either direction of gases and/or the propagation of flame therethrough, comprising discharging liquid carbon dioxide through constricted orifices spaced at suitable intervals along certain portions of said side wall structure to permit sudden expansion of the same to effect its conversion into snow and vapors, maintaining in confinement the snow and vapors formed by said separate discharges until the same merge into elongated masses equal in length to that of said portions of the side wall structure, and finally effecting discharge of snow and vapors from the lengths of said masses to produce the aforesaid curtain.

9. A method of employing liquid carbon dioxide for effecting extinguishment of a fire by the production of a smothering, diluting and/or cooling .curtairr of snow and vapors relative to a fluid surface from which the fire receives fuel vapor, comprising conducting liquid carbon dioxide through a path of confinement that parallels said surface, discharging said liquid through a plurality of constricted orifices spaced at suitable intervals along and all facing radially in the same direction with respect to said path to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining the snow and vapors confined in an expansion chamber that encloses the length of said path until the separate discharges of the same merge along the length of said chamber, and finally effecting discharge of the merged snow and vapors along the entire length of said chamber at a sufliciently high velocity to project a continuous dense curtain of limited thickness over a substantial area of and in parallelism with the fluid surface from which the fire receives combustible fuel forming vapors.

10. A method of employing liquid carbon dioxide for effecting extinguishment of a fire involving highly inflammable liquid which is running down the exterior of the side wall of its confining tank, or the like, comprising conducting liquid carbon dioxide through a path of confinement that extends horizontally around the exterior of the side wall of said tank, discharging said liquid through constricted orifices spaced at suitable intervals along said path to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining the snow and vapors confined in an expansion chamber that encloses the length of said path until the separate discharges of the same merge along the length of the chamber, and finally efiecting discharge of the snow and vapors along the entire length of said chamber to produce a dense curtain which extends continuously around and downwardly over the exterior of the side wall of the tank and in substantial parallelism with the outer surface thereof.

11. A method of employing liquid carbon dioxide for effecting extinguishment of a fire involving highly inflammable liquid which is running down the exterior of the side wall of its confining tank, or the like, comprising conducting liquid carbon dioxide through several parallel paths of confinement that extend horizontally and in vertical spaced relation around the exterior of the side wall of said tank, discharging said liquid through constricted orifices spaced at suitable intervals along said paths to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining the snow and vapors confined in expansion chambers that enclose the lengths of said paths until the separate discharges of the same merge along the length of each chamber, and finally effecting discharge of the snow and vapors along the entire length of each of said chambers to produce one continuous dense curtain of snow and vapor which extends entirely around the exterior of the tank and downwardly over its entire height.

12. A method of employing liquid carbon dioxide for effecting extinguishment of a fire involving a body of highly inflammable liquid confined in a tank, or the like, comprising conducting liquid carbon dioxide through a path of confinement that extends horizontally entirely around the side wall structure of said tank, discharging said liquid through constricted orifices spaced at suitable intervals along said path to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining the snow and vapors confined in an expansion chamber that encloses the length of said path until the separate discharges of the same merge along the entire length of said chamber, and finally effecting discharge of the snow and vapors along the entire length of said chamber to produce a dense curtain which extends continuously across the entire area defined by all of the side wall structure of the tank and in spaced parallelism with the surface of the liquid body.

13. A method of employing liquid carbon dioxide for effecting extinguishment of a fire involving a body of highly inflammable liquid confined in a tank, or the like, comprising conducting liquid carbon dioxide through paths of confinement that extend around the interior and exterior of the side wall of said tank, discharging said liquid through constricted orifices spaced at suitable intervals along said paths to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining in confinement the snow and vapors of each path until the separate discharges through said orifices merge along the length of each path, and finally effecting discharge of the merged snow and vapors to form dense curtains, one of which extends continuously across the entire interior of the tank and the other of which extends continu ously over the entire exterior of the tank wall.

14. A method of employing liquid carbon dioxide for efiecting extinguishment of a fire involv ing a body of highly inflammable liquid confined in a tank, or the like, that is surrounded by a diked-in area, comprising conducting liquid carbon dioxide through paths of confinement that extend around the interior and exterior of the side wall of said tank and around the top of the dike of said area, discharging said liquid through constricted orifices spaced at suitable intervals along said paths to permit sudden expansion of the liquid to effect its conversion into snow particles and vapors, maintaining in confinement the snow and vapors of each path until the separate discharges through said orifices merge along the length of each path, and finally effecting discharge of the merged snow and vapors to form dense curtains, one of which extends continuously across the entire interior of the tank, another of which extends continuously over the ibtl, Hlil; izX HNGUISHERSF entire exterior of the tank wall, and still another of which extends continuously across the dikedin area between the said dike and the bottom portion of the tank.

15. Fire extinguishing apparatus of the type described comprising a tank for confining a body of highly inflammable liquid and having a slot formed in a wall thereof above and in parallelism with the surface of the liquid, carbon dioxide discharge apparatus positioned outside said tank and communicating with the interior thereof through said slot to create a dense curtain of snow and vapors across the entire interior of the tank at a level above the top surface of said liquid body, said apparatus comprising an expansion chamber extending the length of and communicating with the interior of the tank through the tank wall slot, a discharge pipe positioned in and extending the length of said chamber, said pipe having a series of constricted orifices spaced along its length through which liquid carbon dioxide is expanded into the chamber to form snow and vapors which will be discharged through said longitudinal slot, and means for supporting the discharge pipe in said chamber.

16. Fire extinguishing apparatus of the type described comprising the combination with a tank for confining a body of highly inflammable liquid, of carbon dioxide discharge apparatus associated with the side wall structure of said tank to create a dense curtain of snow and vapors across the entire area of the tank at a level above the top surface of said liquid body, said apparatus comprising a horizontally arranged expansion chamber having a longitudinal slot communicating with the interior of the tank, a discharge pipe positioned in and extending the length of said chamber at a level above the chamber slot, said pipe having a straight line series of constricted orifices spaced along its length and on a side thereof facing away from the chamber slot through which liquid carbon dioxide is expanded into the chamber to form snow and vapors which will be discharged through said longitudinal slot, the total area of said orifices and the velocity of discharge through said orifices bearing such a relationship to the area of the slot that the velocity of discharge of the snow and vapors through the slot will be suflicient to maintain the said curtain formation for the desired distance from said chamber, and means for supporting the pipe in said chamber.

17. Fire extinguishing apparatus of the type described comprising liquid carbon dioxide discharge apparatus adapted to create a dense curtain of snow and vapors over a desired area, said apparatus comprising an expansion chamber having a longitudinal slot, a discharge pipe positioned in and extending the length of said chamber, said pipe having a series of constricted ori fices spaced along its length through which liquid carbon dioxide is expanded into the chamber to form snow and vapors which will be discharged through said chamber slot, and means for supporting the discharge pipe in said chamber with the series of constricted orifices all facing away from the chamber slot in the same direction so that the snow and vapors will have to change their direction of travel before arriving at said slot.

18. Fire extinguishing apparatus of the type described comprising the combination with a tank for confining a body of highly inflammable liquid, of carbon dioxide discharge devices associated with both the interior and the exterior of the side wall structure of said tank to create one dense curtain of snow and vapors across the entire interior of the tank at a level above the top surface of said liquid body and to create a second such curtain down the outside of said tank, each of said discharge devices comprising a horizontally arranged expansion chamber having a longitudinal slot, a discharge pipe positioned in and extending the length of said chamber, said pipe having a series of constricted orifices spaced along its length through which liquid carbon dioxide is expanded into the chamber to form snow and vapors Which will be discharged through said longitudinal slot, and means for supporting the discharge pipe in said chamber with the series of constricted orifices facing away from the chamber slot so that the created snow and vapors will be compelled to change their direction of travel before passing through the chamber slot.

19. Fire extinguishing discharge apparatus adapted for producing a dense carbon dioxide snow and vapor curtain of considerable dimensions, said discharge apparatus comprising an elongated expansion chamber having a slot extending the length thereof through which the final curtain forming material is discharged, a discharge pipe positioned in and extending the length of said chamber but offset to one side of the chamber slot, said pipe having a series of constricted orifices spaced along its length on a side thereof away from the chamber slot through which liquid carbon dioxide is expanded into the chamber to form snow and vapors, and

.means for supporting the pipe in said chamber.

20. Fire extinguishing discharge apparatus adapted for producing a, dense curtain type of discharge which is formed of carbon dioxide snow and vapors, said discharge apparatus comprising an elongated expansion chamber havin a longitudinally extending slot through which the curtain forming material is discharged to the atmosphere, a discharge pipe positioned in and extending the length of said chamber but offset to one side of the chamber slot, said pipe having a, series of constricted orifices spaced along its length through which liquid carbon dioxide is expanded into the chamber to form snow and vapors which will be discharged through the chamber slot, and means for supporting the discharge pipe in said chamber so that the series of constricted orifices will face away from the chamber slot to cause the snow and vapors to travel transversely of the chamber and to merge into one continuous mass before arriving at the final discharge slot of the chamber.

21. A method of employing liquid carbon dioxide for effecting extinguishment of a fire involving a body of highly inflammable liquid confined in a tank, or the like, comprising delivering liquid carbon dioxide to said tank, discharging said liquid through constricted orifices spaced at suitable intervals along an elongated zone that is at least equal in length to one horizontal dimension of the tank and is arranged parallel to and at a level above the level of the liquid in the tank to permit sudden expansion of the liquid to effect its conversion into snow particles and vapor, maintaining in confinement the snow particles and vapor until the separate discharges of the same merge along the length of said zone, and finally effecting discharge of said merged snow and vapor along the length of said zone at a sufiiciently high velocity and in such a manner as to produce a. dense, relatively thin curtain which extends over a substantial area of the surface of the liquid.

22. A method of employing liquid carbon dioxide for effecting extinguishment of a fire by creating a, dense, relatively thin, well defined snow and vapor curtain of substantial dimensions in smothering, diluting and/or cooling relation to a surface of burning material, comprising delivering liquid carbon dioxide to an elongated discharge zone that is at least equal in length to one dimension of the surface of said burning material and is arranged in parallelism to said burning CERTIFICATE OF CORRECTION.

February 8, 19141;.

CHARIES A. GETZ.

It is hereby "certified that error appears-in the printed specification of the above nunbered patent requiring correction as follows: Page Z, first column, line 18, for "suface" read surface"; page )4,- second column, line page 10, second column, line 11, for

59, for "an inch read --an inc the said Letters Patent should read --the length; and that o the reccorrection therein that the same may conform t Patent .No. 2,51L1J456l "lengthwise" be read with this ord of the case in the Patent Office.

an of May, A. D. 19141;.

Signed and sealedthis 9th d Leslie Frazer Acti'ng Commissioner of Patents.

CERTIFICATE OF CORRECTION.

February 8, 19th.

PatentNO. 2,5u1,h56.

omnms A. GEIZ.

It is hereby certified that error eppearsin the brinted specification of the above nunbered patent requiring correction as follows: Page Z, first column, line 18, for "suface" read surface"; page )4,- second column, line 59, for' "an inch' read -an inc page 10, second column, line 11, for

and that the said Letters patent should length";

nform to the rec- "lengthwise" read --the tion therein that the same may c0 be read with this correc 0rd of the case in the Patent Office.

Signed and sealed this 9th day of May, A. D. 19ml.

Leslie Frazer r oi Patents.

(Seal) Acting Commissione 

